Cylinder block for an internal combustion engine



Aug. 25, 1964 G. w. CONOVER ETAL 3,145,695

CYLINDER BLOCK FOR AN INTERNAL COMBUSTION ENGINE Original Filed June 8,1960 4 Sheets-Sheet 1 ATTORNEY 25, 19 4 G. w. CONOVER ETAL 3,145,695

CYLINDER BLOCK FOR AN INTERNAL COMBUSTION ENGINE Original Filed June 8,1960 4 Sheets-Sheet 2 INVEN TOR.

ATTORNEY Aug. 25, 1964 G. w. CONOVER ETAL 3,145,695

CYLINDER BLOCK FOR AN INTERNAL COMBUSTION ENGINE Original Filed June 8,1960 (5/ efm J W ATTORZVEY Aug. 25, 1 964 CONOVER ETAL 3,145,695

CYLINDER BLOCK FOR AN INTERNAL COMBUSTION ENGINE 4 Sheets-Sheet 4Original Filed June 8, 1960 I .J I

United States Patent 01 ice 3,145,695 CYLINDER BLOCK FOR AN INTERNALCOMBUSTION ENGINE George W. Conover and Kenneth L. Hulsing, Plymouth,and Joseph G. Koehler, Farmington, Mich, assignors to General MotorsCorporation, Detroit, Mich, a corporation of Delaware Originalapplication June 8, 1960, Ser. No. 34,728, now Patent No. 3,094,190,dated June 18, 1963. Divided and this application June 17, 1963, Ser.No. 288,376 30 Claims. (Cl. 123-41.74)

This invention relates generally to internal combustion engines, andmore particularly to the design and construction of the several enginecomponents and associated accessory mechanisms so that the variouselements may be assembled to provide a multiplicity of configurationsmeeting different engine installation requirements.

This is a divisional application of the copending United Statesapplication, Serial No. 34,728, filed June 8, 1960, now Patent No.3,094,190, issued June 18, 1963, in the names of George W. Conover,Kenneth L. I-Iulsing and Joseph Koehler, and entitled InternalCombustion Engme.

In the design, manufacture and use of internal combustion engines, it isoften desirable to provide a construction that is easily adaptable to awide variety of space limitations, accessory locations and the like. Forexample, in marine use it might be desirable to locate two engines sideby side with the accessories for each engine in an easily accessibleplace, such as between the two engines. This requires an engineconstruction permitting reversibility in the assembly and mounting ofvarious engine components and accessories.

The invention contemplates a series of multicylinder enginesincorporating improved cylinder block constructions symmetry about thelongitudinal vertical plane of the engine and providing alternativeaccessory mounting locations on either side of the engine. Twocounterdriven cam and balance shafts are journaled in the cylinder blockin spaced parallel relation and are interchangeable to permit a cylinderhead having substantial symmetry about its transverse median plane to bereversed end-for-end in its mounting on the cylinder block thusproviding alternative exhaust manifold locations. This block and headsymmetry minimizes tooling requirements for the several engines of theseries and provides maximum accessory versatility to meet variousinstallation requirements.

The improved cylinder block and head components of the invention may becast to provide a relatively light rigid girder-box construction, easyand inexpensive to core, cast, clean and to machine. Such componentsfurther cooperate to provide improved breathing, cooling and lubricationsystems for such engines.

The invention has particular application to internal combustion enginesof the two-cycle uniflow scavenged type and is shown and describedherein for illustrative purposes as incorporated in several engineinstallations of this type. However, the invention is not limited in itsapplication to engines of this particular type and is considered to beapplicable to internal combustion engines generally.

The foregoing and other objects, advantages and features of theinvention will be apparent from the following description havingreference to the accompanying drawings, in which:

FIGURES 1, 2 and 3 are elevational views of a two cycle internalcombustion engine illustrating one of the engine accessory mounting anddrive arrangements permitted by the basic engine structure of theinvention.

FIGURES 4, 5 and 6 are diagrammatic views showing different engineaccessory mounting and drive arrange- 3,145,595 Patented Aug. 25, 1964ments permitted by the basic engine structure of the invention.

FIGURE 7 is a transverse sectional view of a two-cycle internalcombustion engine showing the location of the various parts andillustrating the reversibility permitted by the basic engine components.

FIGURE 8 is a side elevational view of the cylinder block of the engineof FIGURE 7 with portions broken away and sectioned to show certainstructural details.

FIGURE 9 is a top elevational view of the cylinder block of the engineof FIGURE 7 with portions broken away and sectioned to show certainstructural details.

FIGURE 10 is a front elevational view of the cylinder block withportions broken away and sectioned in the direction of the arrowsindicated at 1010 in FIGURE 9.

FIGURE 11 is a rear elevational view of the cylinder block taken in thedirection of the arrows indicated at 11-11 in FIGURE 9.

FIGURE 12 is a transverse sectional view of the cylinder block and istaken substantially in the direction of the arrows and in the plane ofthe line indicated at 1212 in FIGURE 9.

FIGURE 13 is a fragmentary sectional view taken substantially in thedirection of the arrows and in the plane of the line indicated at 1313in FIGURE 12.

Referring more particularly to the drawings, a fourcylinder inlineengine is indicated generally by the reference numeral 10 and isillustrative of a series of twocycle uniflow scavenged multicylinderengines incorporating the invention. Each of the several enginescomprises a cylinder block, indicated generally by reference numeral 11,which is substantially rectangular and has symmetry about a verticalmedian plane passing longitudinally therethrough. This block symmetryprovides a plurality of alternative accessory mounting locations on theopposite side walls thereof as will become hereinafter more apparent.The upper portion of the block 11 encloses several inline cylinderswhich are closed at their upper ends by a cylinder head 12 mounted onthe upper face of the cylinder block. The cylinder head 12 may be of theoverhead valve and injector type and is provided with symmetry about itstransverse median plane to permit end-for-end reversal on the cylinderblock. A cover member 13 is secured to the cylinder head 12 and definesa chamber housing the overhead valve and injector actuating mechanisms.A camshaft 14 and a balance shaft 15 are journaled in the upper portionof the cylinder block 11 and extend longitudinally thereof in parallelspaced relation flanking the cylinder row. These shafts arecounterrotated and carry suitable engine balancing masses adjacent eachend thereof. Shafts 14 and 15 may be interchanged to provide a pluralityof different engine models by the simple expedient of reversing thecylinder head 12 end-for-end. A crankshaft 16 is rotatably supported inthe lower portion of the cylinder block 11 by a plurality of transversewebs 77 and bearing supporting arches 83 and arch secured caps spacedlongitudinally of the block.

An end plate 18 and a housing member 19 are secured to the rear of thecylinder block to enclose the usual drive gears between the crankshaftand the cam and balance shafts. These gears are indicateddiagrammatically in FIGURES 46 by arcuate arrows indicating indicatingdirection of rotation and approximate relative size. The main gear 21 issecured to the end of crankshaft 16 and gears 22 are secured to the endsof the cam and balance shafts 14 and 15. Gears 22 are interengaged toprovide counterrotation of the shafts 14 and 15. Accessory drive gears23 are disposed on opposite sides of the rear face of the block and aredriven by the adjacent gears 22. One of the gears 22 is drivinglyconnected to the crankshaft gear 21 through an idler gear 24 suitablyjournaled 3 on the rear of the cylinder block 11. Idler gear 24 may bemounted on either side of the vertical centerline of crankshaft gear 21for opposite directions of crankshaft rotation to provide propercamshaft timing and driving rotation for alternative mountings of thevarious accessory components.

The lower portion of the gear housing member 19 defines a bell chamberwherein the usual flywheel may be drivingly secured to the rear end ofthe crankshaft. This bell housing portion of the member 19 furthercooperates with the end plate to close the rear crankcase portion of thecylinder block 11. A ring gear carried by the flywheel in the usualmanner is drivingly engageable with the pinion gear of a starter drivemechanism 25. This starter mechanism is preferably of a conventionalelectric or hydraulic motor type and may be mounted on either side ofthe engine.

At the front of the engine, an end plate 26 is secured to and mates witha finished end face formed on the upper portion of the cylinder block.Camshaft 14 and balance shaft 15 extend through this front end plate. Acombined balance weight and V-belt pulley member 27 is secured to theforwardly projecting end of each of these shafts. A verticallyadjustable bracket 28 is secured to the front end plate 26 and bridgesthe pulleys 27 forwardly of the engine and journals a stub shaft 29. AV-belt pulley member 31 is carried by the stub shaft 29 and provides ahub to which a suitable fan may be attached.

The lower crankcase portion of the cylinder block 11 is closed at thefront by a combined cover and gear pump assembly 32 which is secured toand mates with the lower front face of the cylinder block. An oil pan 33is secured to the lower crankcase defining side walls of the cylinderblock 11 and to coextensive bottom surfaces on the gear housing member19 and to pump assembly 32, respectively, and cooperates therewith todefine a crankcase and oil sump chamber 34. The combined cover and gearpump assembly 32, embraces the crankshaft 16 adjacent its forward endwith the gear pump unit being driven directly by the crankshaft tosupply pressurized oil for lubrication and cooling of the various enginecomponents and accessories. A pulley member 35 is secured to the forwardend of the crankshaft 16 and is drivingly connected by V-belts to thefan mounting pulley 31.

The intake of the pump 32 is located in the sump chamber 34 as shown inFIGURE 7. Alternative outlets from the pump discharge chamber areconnectable laterally through alternative passages in the crankcase sidewalls and a support or adapter member 36 to an oil filter unit 37 and anoil cooler unit 38 mountable by the adapter on either crankcase sidewall, depending on desired oil filter and cooler location. The adapterfurther provides return passage means from the filter and cooler backthrough the crankcase side wall to a distribution passage formed in thepump cover. This pump distribution passage extends transversely of theblock and has several outlet ports mating ports opening on the lowerfront end face of the block. These last-mentioned ports lead to severaloil distribution passages extending through the cylinder block.

A centrifugal coolant pump 39 is supported by the oil cooler unit 38 andis drivingly connected by V-belts to the driven pulley of a pivotallyand adjustably mounted generator 62 and to the balance weight pulleymember 27 carried by the adjacent cam or balance shaft. The suctioninlet of the pump 39 is connectable to the thermostatically controlledvalve coolant outlet of the cylinder head, either directly or through asuitable heat exchanger, not shown. To accommodate mounting of the oilcooler, filter and coolant pump assembly on either side of the engine,the discharge of the coolant pump is connectable through the oil coolerto an adjacent one of two alternate coolant inlet ports 99'symmetrically disposed in the opposite side walls of the cylinder block.Each of these ports open to one of two distribution galleries 99extending longitudinally of the block in symmetrical flanking relationto the cylinder row.

An engine governor 41 may be alternatively mounted on either side of therear end plate 18 on the block 11 and driven by the adjacent accessorydrive gear 23. The governor may be of any suitable type and is connectedin a conventional manner to adjust the fuel supply regulating means ofseveral overhead mounted fuel injectors 43. The fuel injectors 43 aremounted in the cylinder head 12 in coaxial relation with the severalinline cylinders 17 and are sequentially operable to supply measuredquantities of fuel to their respective cylinders. Such injectoroperation is provided by camshaft actuation of the several injectorplungers through suitable cam follower linkages 44 of the overheadrocker type.

A fuel circulating pump 45 is mounted with the governor 41 on eitherside of the cylinder block 11. The fuel pump 45 has a fluid inletconnection through a filter unit 46 to the fuel supply tank, not shown,and an outlet connection through a second filter unit 47 to a fueldistribution manifold 48 (FIGURE 7) extending longitudinally of thecylinder head 12. From the manifold 48 the pump supplied fuel iscirculated through the several injector units by suitable fluidconnections for fuel supply and injector cooling purposes. The severalfuel connections are connected through a return manifold 49 extendinglongitudinally of the cylinder head 12 to the fuel supply tank.

Each side wall of the cylinder block 11 has a boss 51 thereon. Thesebosses are finished to provide alternative blower mounting locations onopposite sides of the engine. These bosses further define ports 52 whichextend through the side walls of the block and open to an air box 53extending longitudinally of the block immediately above the crankcase.The ports 52 in the side wall opposite the blower provide inspectionaccess to the engine air box and are normally closed by a cover member54,

A blower assembly illustrated generally by the numeral 55 is of apositive displacement type such as shown and described in United StatesPatent No. 3,059,835 issued October 23, 1962, to Kenneth L. Hulsing andGeorge P. Hanley and entitled Rotary Blower," and need not be describedin complete detail. Briefly, the blower assembly includes a housing 56defining a blower chamber 57 and journaling two lobed impellers 58having pumping interengagement and rotative sealing clearances with theadjacent side walls of the chamber 57. The blower housing has an outletport 59 mating with the air box inlet ports 52 and an inlet portconnectable to a suitable air cleaner assembly, not shown. The lobedimpellers 58 are synchronously driven by two gears illustrateddiagrammatically at 61 in FIGURES 4-6, which in turn are driven by theadjacent accessory gear 23.

It will be noted from the illustrative engine configuration so fardescribed that the engine blower 55 and the started mechanism 25 mightbe alternately mounted on the right side of the engine, as viewed inFIGURE 1, opposite the mounting of the engine accessory group comprisingthe oil cooler and filter assembly 36-38, the coolant pump 39 and thegenerator 62. In this engine configuration, the engine governor 41, thefuel pump 45 and the fuel filters 46 and 47 would be mounted on the sameside of the engine as the oil cooler and filter units. In an alternateengine configuration, the oil cooler and filter assembly, the coolantpump and the generator are mounted on the same side as the blower, theright hand side of the engine as viewed in FIGURE 1, and the startermechanism 25 is mounted on the left hand side of the engine togetherwith the governor, the fuel pump and the fuel filter units.

As shown in FIGURE 7, the upper portions of the cylinder block 11 mountthe several cylinder liners 17 which are inline and closed at theirupper ends by the cylinder head 12. Pistons 63 are reciprocably mountedin each of the several cylinders and cooperate with the closed endsthereof to form expansible combustion chambers therebetween. Each pistonis connected by a wrist pin 64 and a connecting rod 65 to the adjacentcrankpin or throw 66 of the crankshaft. The several crank throws 66carry balancing masses which acts in a conventional manner tocounterbalance the rotating and reciprocating engine unbalance and toreduce the loads imposed on certain of the main bearings.

A belt of inlet ports 67 is formed circumferentially intermediate theends of each liner 17. These ports open to the air box 53. Reciprocationof the several pistons serves to control the admission of scavenging andcharging air through these inlet ports into their respective cylinders.Unifiow scavenging of the exhaust gases is accomplished by thesimultaneous camshaft timed opening of overhead exhaust valves 42. Theseexhaust valves are reciprocably mounted in the cylinder head in theusual manner and control valve seating ports opening to exhaust passages68. The exhaust passages 68 are formed integrally of the cylinder headand terminate in ports 69 opening in the side face of the cylinder head12 opposite the fuel manifolds and the camshaft 14. The several ports 69are connectable to an exhaust manifold 71 having a single outlet at 72and formed symmetrically about the transverse median plane of thecylinder head 12. This symmetry permits the exhaust manifold to besecured to the cylinder head with its outlet directed either upwardly ordownwardly and on either side of the engine with reversal of thecylinder head 12 on the block 11.

As shown in FIGURES 7-13, the cylinder block structure includes apartition wall or deck 75 separating the crankcase chamber 76 from theair box chamber 53. This partition deck extends transversely andlongitudinally between the front, rear and side walls of the block,intersecting and laterally supporting the several crankshaft bearingsupporting webs 77. Vertical ribs 78 and 79 and transverse ribs 81 and82 further reinforce the bearing supporting webs 77 and terminate inmain bearing supporting arches 83. A coolant or water jacket andcamshaft gallery defining portion 84 extends longitudinally of the upperportion of the block and supports the upper combustion chamber ends ofthe several cylinder liners 17 in spaced relation to the partition wall75. This upper block portion 84 is connected to the crankcase definingpartition wall 75 by the front, rear and side walls of the block and bya plurality of columns 85, arranged in pairs and extending therebetweenintermediate the several cylinders and adjacent each end of the block.The several columns 85 are coextensive with the ribs 78 of the bearingarch supporting webs 77 and extend upwardly through the upper cylindersupporting portion 84. These columns are suitably bored and tappedadjacent their upper ends to receive bolts securing the cylinder head tothe upper face of the cylinder block.

A plurality of ports 86 extend through the crankcase defining partition75. These ports are defined by cylindrical muffs or flanges 87 whichextend upwardly from the partition deck and slidably and sealinglysupport the lower ends of the cylinder liners 17. These liner supportingmuffs are reinforced by radial webs extending to the several adjacentcolumns 85. The two intermediate cylinder muffs 87 are furtherreinforced by webs 88 extending radially to the crankcase definingpartition wall 75.

The upper block portion 84 defines a longitudinally extending centralcoolant or water jacket gallery 89 which embraces the upper combustionchamber ends of the several cylinders. This coolant or water jacketgallery is defined between two longitudinally extending decks 91 and 92and flanked by two longitudinally extending galleries 93 whichalternatively mount either the camshaft 14 or the balance shaft 15.These shaft mounting galleries are intersected by annular bosses 93suitably connected to the oil distributing passages of the block. Thinbearing sleeves supported within those several bosses rotatably mountbarrel-type journals spaced longitudinally of the cam and balanceshafts. Ports 93" formed in the block outwardly of the boss 93'interconnect the several compartments formed by the camshaft journalsabove a cam lobe immersing, oil retaining level. Vertical drain passages100 are formed in the side walls of the block intermediate the coolantinlet ports 99' and the blower mounting boss 51 and interconnect theshaft mounting galleries 93 with the lower crankcase defining portion ofthe block. These drain passages are of a size to vent the upper portionsof the engine and de-aerate the oil draining therethrough.

The spaced water jacket defining decks 91 and 92 have a plurality ofports 94 and 95 extending therethrough, respectively. These ports are incoaxial alignment with the ports 86 defined by the lower linersupporting muffs 87 in the partition wall 75. As best seen in FIGURE 7,the ports 94 and 95 slidably support the upper combustion chamber endsof the several cylinder liners 17. The liners are suitably sealed withrespect to the ports by O- ring seals or the like. Partition webs 96extend between the decks 91 and 92 intermediate the several cylindersupporting ports and the columns 85. These partition webs reinforce theupper liner supporting block portion 84 and are provided with ports 97restricting cooling water flow longitudinally of the central waterjacket gallery 89. The partition webs 96 thus divide the central watergallery into a plurality of interconnected water jacket compartmentswhich embrace and equalize coolant flow about the upper ends of theseveral cylinders. These several compartments are connectable upwardlythrough ports 97" to the water jacket gallery of the cylinder head 12. Aplurality of ports 98 connect the compartments of the water jacketgallery of the block laterally to the alternate inlet connected waterdistribution galleries 99 which extend longitudinally of the uppergallery defining portion of the block immediately below the alternatecam and balance shaft galleries. The limited and equalized liquidcooling thus provided serves to minimize the thermal load variationsimposed on the upper combustion chamber ends relative to the relativelycooler intermediate and lower portions of the several liners. Thecooling applied to these lower liner portions is limited to thateffected by air box air flow and conductive heat transfer to the severalliner supporting mufis.

As indicated above and shown and described in detail with reference toFIGURES 9ll in the above-cited Patent No. 3,094,190, the cylinder head12 is reversible end-for-end to provide alternative engine profileconfigurations for the several inline engines. Such head reversibilityalso permits alternative use on either bank of a V-engine derived fromthe basic inline engine design in the manner shown and described incopending United States patent application Serial No. 1,488, filedJanuary 11, 1960, in the names of Harold H. Albinson, George P. Hanley,Kenneth L. Hulsing, Harvey G. Humphries, and John J. May, and entitledTwo-Cycle Internal Combustion Engine. To provide this end-for-endreversibility, each cylinder head 12 is provided with symmetry about itstransverse median plane.

The several engine and accessory components thus permit a number ofdifferent engine arrangements or configurations determined by thedesired direction of crankshaft rotation; by cylinder head orientationrelative to the block thereby locating the exhaust manifold 71 and thecamshaft 14; by the mounting of the various timing gear drivenaccessories including the blower 55, the governor 41 and the startermechanism 25; and by the mounting of the accessory group comprising theoil filter and cooler, the water pump and the generator. Several of thevarious configurations permitted by possible combinations of theseelements are shown in FIGURES 1-3 and indicated diagrammatically in eachof FIGURES 4-6. The alternative mounting locations of the variouscomponents are indicated in these diagrammatic views by appropriateoutlines identified by their respective reference numerals. Theseseveral views are taken looking forwardly of the engine from the rear.

FIGURES l and 4 show the relative positions of the blower 55, exhaustmanifold 71 and camshaft 14 of engines arranged for counterclockwiserotation of the crankshaft 16. FIGURES 5 and 6 show the same respectiverelative positions between the blower, exhaust manifold and camshaft asthose of FIGURES 1 and 4 but in engines arranged for clockwise rotationof the crankshaft. The indicated mounting of the oil filter and coolerand thus of the water pump and generator in FIGURES 5-6, however, is onthe opposite side of the engine to that shown in each of thecorresponding FIGURES l and 4. Thus the several corresponding enginesmay be paired in multi-engine installations wherein the crankshafts mustnecessarily be counterrotated, as in a-twin screw marine drive. In suchinstallations, it is generally desirable to have the various accessoryappurtenances accessible either to a central gallery or outboard-of thepower package.

For each of the several engines shown in FIGURES 1 and 46, analternative engine configuration may be achieved by mounting the oilfilter and cooler, the water pump and generator on the opposite side ofthe engine thus permitting paired engine installations whereinthe'crankshafts are required to have the same hand of rotation. Similarvariations in engine configurations may be achieved by varying themounting locations of the engine governor 41 and of the starter unit 25.The indicated versatility in accessory mounting and resultant engineconfiguration thus permits use of the basic engine to meet a wide rangeof installation requirements.

From the foregoing description of the several illustrative inlineengines and their accessory components, it will be seen that the variousobjectives and advantages of the invention have been achieved. Theresultant engine structures provide a plurality of different enginemodels and alternative accessory mounting locations, and the improvedcylinder block and cylinder head constructions provide two-cycle enginesof relatively high power density, provide improved cooling systems forsuch engines, provide improved lubrication and breathing, and provideimproved overall engine efficiency.

It will be apparent to those skilled in the art, that variousmodifications might be made from the several illustrative embodiments ofthe invention without departing from the spirit and scope of theinvention as defined in the following claims.

What is claimed is:

1. A cylinder block for a two-stroke unifiow scavenged internalcombustion engine having a plurality of inline cylinders, said cylinderblock having substantial symmetry about a longitudinally extendingmedian plane and comprising:

a pair of end walls;

a pair of side walls structurally connected to said end walls;

a lower crankcase portion within said walls receiving and supportingsaid cylinders; an upper portion within said walls receiving andsupporting said cylinders and having parallel cam and balance shaftmounting galleries extending longitudinally thereof and symmetricallydisposed on opposite sides of said cylinders, either of said galleriesbeing adapted to receive a camshaft or a balance shaft;

and a plurality of paired transversely spaced parallel columns inwardlyspaced from said side walls for supporting and connecting said upper andlower portions.

2. A cylinder block for a two-stroke internal combustion engine having aplurality of inline cylinders, said cylinder block comprising:

a pair of spaced vertical end walls;

a pair of spaced vertical side walls structurally connecting said endwalls;

a first partition wall extending between and structurally connectingsaid end walls and said side walls and being spaced from the upper andlower edges thereof, said first partition wall dividing the spaceenclosed by said end walls and said side walls into an upper cylinderreceiving portion and a lower crankcase portion;

5 a plurality of spaced crankshaft supporting bearing webs dependingfrom said first partition wall and extending transversely across saidlower crankcase portion and structurally secured to said side walls;

means formed on the upper side of said first partition wall and in saidupper cylinder receiving portion for receiving and supporting saidcylinders;

21 second partition wall extending between and structurally connectingsaid end and side walls, said upper partition wall having means formedtherein for receiving and supporting said cylinders in spaced relationto said first partition wall formed means;

a plurality of paired transversely spaced parallel columns inwardlyspaced from said side walls extending between said upper partition walland said lower partition wall and aligned with said bearing webs forstructurally supporting and connecting said partition walls and bearingwebs;

and a pair of spaced camshaft and balance shaft mounting galleriesextending longitudinally of and symmetrically disposed on laterallyopposite sides of said upper cylinder receiving portion, said galleriesbeing adapted to receive alternatively either a camshaft or a balanceshaft.

3. A cylinder block for a two-stroke internal combus- 30 tion enginehaving a plurality of inline cylinders, said cylinder block havingsubstantial symmetry about a longitudinal median plane and comprising:

a pair of spaced end walls;

a pair of side walls structurally connecting said end walls;

a first longitudinal and transverse partition wall dividing saidcylinder block into an upper cylinder portion and a lower crankcaseportion;

a plurality of parallel lateral and transverse structural membersdisposed between said side walls, said members including crankshaftbearing support webs disposed in said lower crankcase portion and spacedsupport columns disposed in said upper cylinder portion and spacedinwardly from said side walls;

a second longitudinal and transverse wall spaced from said firstpartition wall and structurally connecting said end walls and said sidewalls;

means formed in said first partition wall and said second wall forreceiving and supporting said cylinders;

and a pair of longitudinal shaft mounting galleries in said upperportion symmetrically spaced on opposite sides of the longitudinalmedian plane of said cylinder block and of equal size, either of saidgalleries being adapted to receive a balance shaft when the other ofsaid galleries receives a camshaft.

4. A cylinder block for a two-stroke internal combustion engine having aplurality of inline cylinders, said cylinder block having substantialsymmetry about a longitudinal median plane and comprising:

a pair of spaced end walls and a pair of spaced side walls, said wallsbeing structurally connected and each said side walls having a portformed therein, said ports being symmetrically disposed relative to thelongitudinal median plane of said cylinder 65 block;

a longitudinal and transverse lower partition wall connecting said sidewalls and said end walls and below said ports, said partition wallforming upper and lower cylinder block portions;

a plurality of spaced and parallel transverse and lateral bearingsupporting webs in said lower portion structurally connecting saidpartition and said side walls;

an upper partition disposed longitudinally and transversely in saidupper portion and above said ports in said side walls;

a plurality of pairs of columns in said upper portion disposed abovesaid bearing supporting webs and structurally supporting said upperpartition;

a pair of spaced and parallel shaft galleries in said upper portionsymmetrically disposed on opposite sides of the longitudinal medianplane of said cylinder block, said galleries being of equal size andadapted to receive alternatively a camshaft or a balance shaft for saidengine;

and a mounting pad formed on each of said side walls about said ports,both of said pads being adapted to receive an air box charging blowerand both of said pads being adapted to receive a closure member, wherebya closure member is mounted on one of said pads when a blower is mountedon the other of said pads.

5. A cylinder block for a two-stroke internal combustion engine having aplurality of inline cylinders, a first accessory group including ablower and a second accessory group including an oil cooler assembly, awater pump and a generator, said cylinder block having substantialsymmetry about a longitudinal median plane and comprising:

spaced end walls, one of said end walls having oil and water passagesformed therein;

spaced side walls strucq'urally connecting said end Walls and havingair, water and oil passages formed therein;

internal partition and support means for supporting and strengtheningsaid end walls and said side walls;

a pair of symmetrically spaced shaft galleries extending longitudinallyin said cylinder block, said galleries being of the same size andadapted to receive interchangeably a camshaft and a balance shaft topermit rotation of the camshaft in either direction;

and means for mounting said first accessory group on each of saidsidewalls and symmetrically disposed with respect to the longitudinalmedian plane of said cylinder block;

and means for mounting said second accessory group on laterally oppositesides of said one end wall,

whereby the first accessory group is mounted on one side of saidcylinderblock and the second accessory group is mounted on the otherside of said cylinder block in accordance with the location anddirection of rotation of the camshaft.

6. A cylinder block for a two-stroke internal combustion engine having aplurality of inline cylinders and an air box charging blower, saidcylinder block having substantial symmetry about a longitudinal medianplane and comprising:

spaced end walls;

spaced side walls structurally connecting said end walls and having airpassages formed therethrough;

internal partition and support means for supporting and strengtheningsaid end walls and said side walls;

a pair of symmetrically spaced shaft galleries extending longitudinallyof said cylinder block, said galleries being of the same size andadapted to receive interchangeable counterdriven cam and balance shafts;

and means formed outwardly of the air passages on each of said sidewalls symmetrically of the longitudinal median plane to permitalternative mounting of the blower on either side of said cylinder blockin accordance with the location and direction of rota tion of thecamshaft.

7. A cylinder block for a two-stroke internal combustion engine having aplurality of inline cylinders, an air box charging blower, a starter, agovernor and a fuel pump, said cylinder block having substantialsymmetry about a longitudinal median plane and comprising:

spaced end walls;

spaced side walls structurally connecting said end walls and having airpassages formed therethrough;

internal partition and support means for supporting and strengtheningsaid end walls and said side walls;

a pair of symmetrically spaced shaft galleries extending longitudinallyof said cylinder block, said galleries being of the same size andadapted to receive interchangeably a camshaft and a balance shaft topermit rotation of the camshaft in either direction;

means for mounting the starter laterally of said side walls andsymmetrically of the longitudinal median plane to permit mounting of thestarter oneither side of said cylinder block;

mounting bosses formed on each of said side walls outwardly of said airpassages and adapted to mount the air box charging blower, said bossesbeing symmetrically disposed on said side walls relative to thelongitudinal median plane to permit mounting of the blower on eitherside of said cylinder block;

and means for mounting the governor and fuel pump disposed symmetricallyof said side walls and of the longitudinal median plane to permitmounting of the governor and the fuel pump on the side of said cylinderblock opposite to the side on which the blower is mounted.

8. A cylinder block for a two-stroke uniflow scavenged internalcombustion engine, said cylinder block having substantial symmetry abouta longitudinally extending median plane, said block comprising a lowerportion defining a crankcase chamber and having a plurality of axiallyaligned crankshaft journal bearings supported in spaced parallelrelation by webs and reinforcing struts extending transversely of saidcrankcase chamber,

said lower crankcase defining portion further having an inline row ofports extending therethrough intermediate the several bearing supportingwebs and defined in part by cylindrical flanges,

a plurality of cylinder liners each supported at its lower end by one ofsaid flanges and each having a plurality of air inlet ports thereinspaced circumferentially above its supporting flange,

an upper portion of said block extending longitudinally of said cylinderrows in parallel spaced relaltion to said lower portion and supportingthe upper ends of said liners above the inlet ports,

said upper support portion defining two parallel galleries extendinglongitudinally of the cylinder row rotating cam and balance shafts,

said upper and lower portions being structurally interconnected by endand side walls integral and coextensive therewith and by a plurality ofpaired transversely spaced parallel columns extending therebetweenintermediate the several cylinders and adjacent the front and rear endwalls, said columns being spaced from the side walls of said block andcoextensive with said crankcase web and reinforcing struts,

and said upper and lower block portions, walls, liners and linersupporting flanges defining a scavenging air receiving chamber extendinglongitudinally of the block and around the liner supporting flanges andthe portions of the several cylinder liners intermediate the supportedends thereof.

9. In a two-stroke uniflow scavenged internal combus tion engineincluding a cylinder block as set forth in claim 8,

said side walls having alternative air inlet ports extendingtherethrough and symmetrically disposed with respect to said medianplane,

said air inlet ports each being defined by a peripheral boss adapted tomount and support a compressor unit and including two end boss portionsextending between said upper and lower block portions.

10. A cylinder block structure for a two-stroke uniflow scavengedinternal combustion engine, said cylinder block structure havingsubstantial symmetry about a longitudinally extending median plane andcomprising a lower portion defining a crankcase chamber, a plurality ofaxially aligned crankshaft journal bearings supported in spaced parallelrelation by webs and reinforcing struts extending transversely of saidcrankcase defining portion,

said crankcase portion having an inline row of ports extendingtherethrough intermediate the bearing supporting webs and defined inpart by cylindrical said shaft mounting galleries and embracing theupper flanges, ends of the several cylinders a plurality of cylinderliners each supported at its lower and two water distribution galleriessymmetrically end by one of said flanges, each of said liners havingflanking and extending longitudinally of the cylinder a plurality of airinlet ports formed circumferentially row immediately below said shaft'mounting galthercof intermediate its ends, 15 leries,

an upper portion of said block extending longitudinally said waterjacket and distribution galleries being interof said cylinder rows inparallel spaced relation to connected by a plurality of ports extendingtheresaid lower portion andsealingly supporting the upper between, endsof said liners above the inlet ports, said upper said upper and lowerblock portions beingstructurally support portion defining interconnectedby end and side walls integral and two parallel shaft mounting galleriessymmetrically coextensive therewith and by a plurality of pairedflanking and extending longitudinally of the cylinder transverselyspaced parallel columns extending thererow, said shaft mountinggalleries each having a plubetween intermediate the several cylindersand adjarality of spaced bearing supporting bosses dividing cent thefront and rear end walls, said columns bethe gallery into a plurality ofcompartments and ing spaced from the side walls of said block and havingaligned ports outboard of said bosses intercoextensive with saidcrankcase webs and reinforcing connecting the several shaft gallerycompartments, Struts,

a water jacket gallery extending longitudinally between and said upperand lower block portions, walls, and said shaft mounting galleries andembracing the cylinders defining a scavening air receiving chamber uppersupported ends of the ev ral cylinder liner extending longitudinally ofand extending around and two water distribution galleries symmetricallyflanking and extending longitudinally of the cylinder row immediatelybelow said shaft mounting galleries, said the several cylindersintermediate the water jacketed and crankcase supported ends thereof.12. In a two-stroke uniflow scavenged internal combustion engineincluding a cylinder block as set forth in water jacket and distributiongalleries being inter- Claim connected through a plurality of portsextending a crankshaft journaled in said crankcase supportedtherebetween, bearings,

said upper and lower portions being structurally intera camshaftrotatably mounted in one of said shaft connected by end and side wallsintegral and coextenmounting galleries and having longitudinally spacedsive therewith and by a plurality of paired trans- Cam lobes thereon,

versely spaced parallel columns extending therebetween intermediate theseveral cylinders and adjacent the front and rear end walls, saidcolumns being spaced from the side Walls of said block and coextensivewith said crankcase web and reinforcing struts,

partition webs extending through said upper portion between the severalcylinders and dividing said water jacket gallery into a plurality ofcompartments embracing the upper supported ends of the several liners,said partition webs further cooperating with said columns to defineports intermediate the several water jacket compartments,

and said portions, walls, liners and liner supporting flanges defining ascavening air receiving chamber extending longitudinally of the blockand extending around the liner supporting flanges and the portions ofthe several cylinder liners intermediate the water jacketed andcrankcase flange supported ends thereof.

11. A cylinder block for a two-stroke uniflow scavenged a balance shaftrotatably mounted in the other of said shaft galleries, phased enginebalancing. masses secured to opposite ends of said cam and balanceshafts,

timing gear means associated with one end of said block and drivinglyinterconnecting said cam and balance shafts for counter rotation inphased relation to the rotation of said crankshaft,

the upper portions of said block side walls having alternative air inletports opening to the scavenging air receiving chamber, said alternativeair inlet ports being symmetrically disposed with respect to said medianplane and defined by a peripheral boss in cluding two parallel and bossportions extending bebetween said upper and lower block portions andadapted to mount and support an engine driven compressor unitalternatively mountable on either side of the engine,

said compressor unit being mounted on one of said side walls in matingrelation with the air inlet port thereof and having a driving connectionthrough said timing gear means to effect air pumping displacementinternal combustion engine, said cylinder block having substantialsymmetry about a longitudinally extending median plane comprising alower portion defining a crankcase chamber, a plurality of axiallyaligned crankshaft journal bearings to said receiving chamber for agiven hand of crankshaft rotation. 13. In a two-stroke uniflow scavengedinternal combustion engine including a cylinder block as set forth inclaim 11,

supported in spaced parallel relation by webs and reinforcing strutsextending transversely of said crankcase defining portion,

a plurality of inline cylinders extending upwardly through saidcrankcase portion intermediate the bearing supporting webs, each of saidcylinders having a plurality of air inlet ports formed circumferentiallythereof intermediate its ends,

13 cured to opposite ends of said cam and balance shafts,

timing gear means associated with one end of said block and drivinglyinterconnecting said cam and balance shafts for counterrotation inphased relation to the rotation of said crankshaft,

the lower crankcase defining portions of said block side walls definingalternative oil cooler and filter mounting locations adjacent one endthereof and having oil distribution passages extending longitudinallyand transversely thereof,

a combined oil filter and cooler assembly alternatively mounted on oneof said side wall locations,

an oil pump unit mounted on and closing the end of said block oppositesaid timing gear means and having fluid connection with the blockdefined oil distribution passages, said pump unit being drivinglyconnected to said crankshaft for fluid pumping displacement from saidcrankcase chamber through said oil filter and cooler assembly to the oildistribution passages defined by said block,

the upper portions of said block side walls having alternative waterinlet ports opening to said water distri bution galleries symmetricallyof said median plane,

said oil cooler and filter unit having a cooling water outlet connectedto the water inlet port of the adjacent block side wall,

and a water circulating pump mounted on said combined oil cooler andfilter unit and having a discharge connection therethrough to theadjacent water inlet port, said circulating pump including waterdisplacing means drivingly connected to the adjacent one of said cam andbalance shafts for rotation therewith.

14. In a two-stroke uniflow scavenged internal combustion engineincluding a cylinder block as set forth in claim 11,

a crankshaft journaled in said crankcase supported bearings,

a camshaft rotatably mounted in one of said shaft mounting galleries andhaving longitudinally spaced cam lobes thereon operable to sequentiallyactuate associated valve and fuel injector mechanisms,

a balance shaft rotatably mounted in the other of said shaft galleries,phased engine balancing masses secured to opposite ends of said cam andbalance shafts,

timing gear means associated with one end of said block and drivinglyinterconnecting said cam and balance shafts for counterrotation inphased relation to the rotation of said crankshaft,

the lower crankcase defining portions of said block side walls definingalternative oil cooler and filter mounting locations and oildistribution passages extending longitudinally and transversely thereof,

a combined oil filter and cooler assembly alternatively mounted on oneof said side wall locations,

an oil pump unit mounted on the end of said block opposite said timingbear end, said pump unit having fluid connection and being drivinglyconnecetd to said crankshaft for fluid pumping displacement from saidcrankcase chamber through said oil filter and cooler assembly to the oildistribution passages defined by said block,

the upper portions of said block side walls having alternative waterinlet ports opening to said water distribution galleries and alternativeair inlet ports opening to the scavenging air receiving chamber, saidalternative water and air inlet ports being symmetrically disposed withrespect to said median plane,

said air inlet ports each being defined by a peripheral ing between saidupper and lower block portions and boss including two parallel end bossportions extendadapted to mount and support an engine driven compressorunit mountable on either side of the engine,

said compressor unit being mounted on one of said side walls in matingrelation with the air inlet port thereof and having a driving connectionthrough said timing gear means to effect air pumping displacement tosaid receiving chamber for a given hand of crankshaft rotation,

the other of said air inlet ports being closed by a cover member securedto the port defining peripheral boss,

said oil cooler and filter unit having a cooling water outlet connectedto the water inlet port of the adjacent block side wall,

and a water circulating pump mounted on said combined oil cooler andfilter unit and having a discharge connection therethrough to theadjacent block inlet, said circulating pump including water displacingmeans drivingly connected to the adjacent one of said cam and balanceshafts for rotation therewith.

15. A cylinder block for a two-stroke uniflow scavenged internalcombustion engine, said cylinder block having substantial symmetry abouta longitudinally extending median plane and comprising a lower crankcasedefining portion,

a plurality of inline cylinders supported by and extending upwardly fromsaid crankcase portion, said cylinders each having a plurality of airinlet ports circumferentially formed intermediate its ends,

an upper portion of said block extending longitudinally of said cylinderrow and supporting the upper ends of said cylinders above their airinlet ports, said upper support portion defining two parallel cam andbalance shaft mounting galleries symmetrically flanking and extendinglongitudinally of the cylinder row,

a water jacket gallery extending longitudinally between said shaftmounting galleries and embracing the upper ends of the several cylindersand two water distribution galleries symmetrically flanking andextending longitudinally of the cylinder row immediately below saidshaft mounting galleries,

said water jacket and distribution galleries being interconnected by aplurality of ports extending therebetween,

said upper and lower block portions being structurally interconnected byend and side walls integral and coextensive therewith and by a pluralityof paired transversely spaced parallel columns extending therebetweenintermediate the several cylinders and adjacent the front and rear endwalls,

said columns being spaced from the side walls of said block and saidupper and lower block portions, walls and cylinders defining ascavenging air receiving chamber embracing the several cylindersintermediate the water jacketed and crankcase supported ends thereof.

16. In a cylinder block for a two-stroke uniflow scavenged internalcombustion engine as set forth in claim 15, said cylinder block having aplurality of cylindrical bearing supporting bosses spaced longitudinallyof the shaft mounting galleries, said bosses being located between theseveral cylinders and adjacent each end of the cylinder blo ck anddividing the camshaft gallery into a plurality of lubricant receivingcompartments,

and said cylinder block further defining a plurality of aligned portsoutwardly of the several bearing supporting bosses, said aligned portsinterconnecting the several gallery compartments and being of a size tovent and drain the several camshaft gallery compartments longitudinallyof the cylinder block above a cam lobe immersing lubricant level.

17. In a two-stroke uniflow scavenged internal combustion engineincluding a cylinder block as set forth in claim 15 said block having aplurality of cylindrical bearing supporting bosses spaced longitudinallyof and dividing said galleries into a plurality of lubricant receivingcompartments adjacent the several cylinders,

said cylinder block defining drain passages connecting each of saidshaft mounting galleries to the crankcase adjacent one end of the block,

said block further having a plurality of longitudinally aligned drainportsformed outwardly of and extending through the several bearingsupporting bosses to interconnect the several lubricant receivingcompartments of each shaft mounting gallery,

said drain ports being located slightly above the bearing supportingsurfaces of the adjacent bosses and being of a size to drain and ventthe several shaft mounting gallerycompartments longitudinally above acam lobe immersing level and through said drain passages to saidcrankcase chamber and said block further defining lubricant supplyingpassage means operable to meter lubricant to the several bearing bossesand lubricant receiving compartments.

18. In a two-stroke unifiow scavenged internal combustion engineincluding a cylinder block as set forth in claim 15,

the lower crankcase defining walls of said block defining alternativeoil cooler mounting locations and having oil distribution passagesextending longitudinally and transversely of the block,

an oil cooler alternatively mounted on one of said crankcase definingside walls,

an oil pump mounted on said block and drivingly connected to said engineto effect oil pumping displacement from said crankcase through said oilcooler to the oil distribution passages of said block,

said oil cooler having a cooling water outlet connected to the waterdistribution gallery on the adjacent side of the block,

and a water circulating pump mounted on said oil cooler and drivinglyconnected to said engine to effect water pumping displacement throughsaid cooler to the adjacent water distribution gallery.

19. In a cylinder block as set forth in claim 15,

said cylinder block side walls having alternative air inlets opening tothe scavenging air receiving chamber symmetrically of said median plane,

each of said air inlets being defined by a peripheral boss and twoparallel bosses extending between said upper and lower block portionsand adapted to mount and support an engine driven compressor unititternatively on either side wall of the engine.

20. In a two-stroke uniflow scavenged internal combustion engineincluding a cylinder block as set forth in claim 15,

a crankshaft journaled in said crankcase,

a camshaft rotatably mounted in one of said shaft mounting galleries andhaving cam lobes thereon operable to sequentially operate associatedvalve and injector actuating mechanisms,

a balance shaft rotatably mounted in the other of said shaft galleries,

phased engine balancing means secured to opposite ends of said cam andbalance shafts,

timing gear means drivingly connecting said cam and balance shafts forcounterrotation in phased relation to said crankshaft,

a cylinder head mounted on said upper block portion and closing theupper outwardly disposed ends of said cylinders, said cylinder headbeing symmetrical about its transverse median plane for end-to-endreversible mounting on the cylinder block and having struts extendingtherethrough alignable with the columns of said block and adapted toreceive mounting bolts securing said head to the columns of said block,

said cylinder head having exhaust passages and overenged internalcombustion engine, said cylinder block having substantial symmetry abouta longitudinally extending median plane and comprising a lower crankcasedefining portion,

a plurality of inline cylinders supported by and extending upwardly fromsaid crankcase portion, said cylinders having each a plurality of airinlet ports formed circumferentially between its ends,

an upper portion of said block extending longitudinally of said cylinderrow and supporting the upper ends of said cylinders above the air inletports, said upper support portion defining two parallel cam and balanceshaft mounting galleries symmetrically flanking and extendinglongitudinally of the cylinder row a Water jacket gallery extendinglongitudinally between said mounting galleries and embracing the upperends of the several cylinders and two water distribution galleriessymmetrically flanking and extending longitudinally of the cylinder rowimmediately below said shaft mounting galleries,

said water jacket and distribution galleries being interconnected by aplurality of ports extending therebetween,

said upper and lower block portions being structurally interconnected byend and side walls integral and coextensive therewith,

and said upper and lower block portions, walls and cylinders defining ascavenging air receiving chamber embracing the several cylindersintermediate the Water jacketed and crankcase support ends thereof.

22. In an internal combusion engine, a cylinder block comprising a lowercrankcase defining portion,

a plurality of inline cylinders supported by and extending upwardly fromsaid crankcase portion,

an upper portion of said block extending longitudinally of said cylinderrow and supporting the upper ends of said cylinders above the crankcaseportion,

said upper and lower block portions being structurally interconnected byend and side walls integral and coextensive therewith,

said upper support portion defining a camshaft mounting galleryextending longitudinally of the inline cylinder row and a water jacketgallery embracing the upper ends of the several cylinders,

a plurality of bearing bosses intersecting the shaft mounting gallerylongitudinally between the several cylinders and adjacent each endthereof and dividing said gallery into a plurality of lubricantreceiving compartments, said bearing bosses defining a plurality ofaxially aligned cylindrical surfaces adapted to support the spacedjournal bearings of a camshaft rotatably mountable therein and furtherdefining a plurality of ports spaced outwardly of the cylinder row andof the cylindrical bearing supporting surfaces therethrough andlongitudinally aligned to interconnect the several lubricant receivingcompartments above a cam lobe immersing level.

23, In an internal combustion engine,

a cylinder block having an inline row of cylinders and defining acamshaft mounting gallery extending longitudinally of the inlinecylinder row,

a plurality of bearing bosses intersecting the shaft mounting gallerylongitudinally between the several 17 cylinders and adjacent each endthereof and dividing said gallery into a plurality of lubricantreceiving compartments, said bearing bosses defining a plurality ofaxially aligned cylindrical surfaces adapted to support the spacedjournal bearings of a camshaft mountable therein and further defining aplurality of ports spaced outwardly of the cylinder row and of thecylindrical bearing supporting surfaces therethrough and longitudinallyaligned to interconnect the several lubricant receiving compartmentsabove a cam lobe immersing level.

24. In an internal combustion engine as set forth in claim 23, saidcylinder block further defining a lubricant drain passage connected tosaid camshaft gallery between two of the bearing supporting bossestherein,

and said aligned ports and passage being of a size to continuously ventand drain the supplied lubricant longitudinally from the severalcamshaft gallery compartments and through said passage.

25. In an internal combustion engine, a cylinder block havingsubstantial symmetry about a longitudinally extending median plane andcomprising a lower block portion defining a crankcase chamber,

a plurality of inline cylinders supported by and extending from saidlower crankcase portion,

and an upper block portion supporting said cylinders in spaced relationto the lower crankcase portion and defining two parallel cam and balanceshaft mounting galleries symmetrically flanking and extendinglongitudinally of the aligned cylinder row,

a plurality of bearing bosses dividing the shaft mounting gallerieslongitudinally between the several cylinders and adjacent each endthereof into a plurality of lubricant receiving compartments,

and said bearing bosses further defining a plurality of longitudinallyaligned drain ports outwardly reinforcing and interconnecting theseveral lubricant receiving compartments above a cam lobe immersinglevel.

26. In an internal combustion engine, a cylinder block havingsubstantial symmetry about a longitudinally extending median plane andcomprising a lower block portion defining a crankcase chamber,

a plurality of inline cylinders supported by and extending from saidlower crankcase portion,

and an upper block portion supporting said cylinders in spaced relationto the lower crankcase portion and defining two parallel cam and balanceshaft mounting galleries symmetrically flanking and extendinglongitudinally of the aligned cylinder row,

a water jacket gallery embracing the upper ends of the severalcylinders,

and two water distribution galleries symmetrically flanking andextending longitudinally of the cylinder row immediately below saidshaft mounting galleries,

said upper and lower block portions being structurally interconnectingby end and side Walls integral and coextensive therewith,

said upper block portion having a plurality of longitudinally spacedbearing bosses dividing the shaft mounting galleries into a plurality oflubricant receiving compartments and transversely reinforcing said upperblock portion,

and said upper block portion further having a plurality oflongitudinally aligned drain ports interconnecting the several lubricantreceiving compartments outwardly of said bearing bosses above a cam lobeimmersing level.

27. In an internal combustion engine as set forth in claim 26, saidcylinder block further defining pasages connecting said crankcasechamber to each of said galleries between two of the bearing supportingbosses therein,

and said aligned ports and passages being of a size to continuously ventand drain the supplied lubricant longitudinally from the several gallerycompartments and through said passage to the crankcase chamber. 28. Acylinder block for a two-stroke internal combustion engine havingsubstantial symmetry about a longitudinally extending median plane andcomprising a lower block portion defining a crankcase chamber,

a plurality of aligned cylinders each supported by and extendingupwardly from said lower crankcase portion,

and an upper block portion supporting said cylinders in spaced relationto the lower crankcase portion above their inlet ports and defining twoparallel cam and balance shaft mounting galleries symmetrically flankingand extending longitudinally of the aligned cylinder row,

a plurality of cylindrical bearing supporting bosses longitudinallydividing the shaft mounting galleries into a plurality of lubricantreceiving compartments,

and further defining a plurality of longitudinally aligned portsinterconnecting the several gallery compartments outwardly of thebearing supporting bosses and being of a size to vent and drain theseveral camshaft gallery compartments longitudinally of the cylinderblock above a cam lobe immersing level.

29. In an internal combustion engine as set forth in claim 28, saidcylinder block further defining passages connecting said crankcasechamber to each of said galleries between two of the bearing supportingbosses therein,

and said aligned ports and passages being of a size to continuously ventand drain the supplied lubricant longitudinally from the several gallerycompartments and through said passage to the crankcase chamber.

30. A cylinder block for a two-stroke uniflow scavenged internalcombustion engine, said cylinder block having substantial symmetry abouta longitudinally ex tending median plane and comprising a lowercrankcase defining portion,

a plurality of inline cylinders supported by and extending upwardly fromsaid crankcase portion, said cylinders each having a plurality of airinlet ports formed circumferentially between its ends,

an upper portion of said block extending longitudinally of said cylinderrow and supporting the upper ends of said cylinders above the crankcaseportion, said upper support portion defining two parallel cam andbalance shaft mounting galleries symmetrically flanking and extendinglongitudinally of the cylinder row,

a water jacket gallery extending longitudinally between said shaftmounting galleries and embracing the upper ends of the severalcylinders,

and two water distribution galleries symmetrically flanking andextending longitudinally of the cylinder row immediately below saidshaft mounting galleries,

said water jacket and distribution galleries being interconnected by aplurality of ports extending therebetween,

said upper and lower block portions being structurally interconnected byend and side walls integral and coextensive therewith and said upper andlower block portions, walls and cylinders defining a scavenging airreceiving chamber embracing the several cylinders intermediate the waterjacketed and crankcase supported ends thereof,

said upper block portion further having a plurality of cylindricalbearing supporting bosses longitudinally dividing the shaft mountinggalleries between the several cylinders and adjacent each end of thecylinder block into a plurality of lubricant receiving compartments,

lubricant supply means operable to continuously meter lubricant tocertain of said bearing supporting bosses of the cylinder block above acam lobe immersing and therefrom to the several lubricant receivinglevel. compartments,

and the several bearing supporting bosses further defining a pluralityof longitudinally aligned ports out- 5 Wardly interconnecting theseveral gallery compartments and being of a size to vent and drain theseveral camshaft gallery compartments longitudinally References Cited inthefile of this patent UNITED STATES PATENTS Brecht Nov. 14, 1939Albinson Dec. 27, 1955 v STATES PATENT, OFFICE CERTIFICATE OF CORRECTIONPatent No; 3, 145, 95 V I I August 25', 19 4 George W, Conover et a1,

It is hereby certified that error appearsin the above numbered pat- Icut requiring correction and that the said Letters Patent should readasv corrected below Column 1, line 36, before "symmetry" insert havingsubstantial column 2, line 63, strike out "indicating", secondoccurrence; column 3, line 57, after "mating" insert with line 75, after"two" insert coolant column 5, line 4, for "acts" read act column 10,line 46, after "row" insert and adapted. to interchangeably mountcounter-; column 13, line 57, for "beer" read gear line 71, after"extend" insert ing between said upper and lower block portions andcolumn 15, line 49, for "it" read alcolumn 16, line 39, for "support"read supported Signed and sealed this 22nd day of December l964a (SEAL)Attest:

ERNEST W. SWIDER EDWARD J, BRENNER Attesting Officer I Commissioner ofPatents

1. A CYLINDER BLOCK FOR A TWO-STROKE UNIFLOW SCAVENGED INTERNALCOMBUSTION ENGINE HAVING A PLURALITY OF INLINE CYLINDERS, SAID CYLINDERBLOCK HAVING SUBSTANTIAL SYMMETRY ABOUT A LONGITUDINALLY EXTENDINGMEDIAN PLANE AND COMPRISING: A PAIR OF END WALLS; A PAIR OF SIDE WALLSSTRUCTURALLY CONNECTED TO SAID END WALLS; A LOWER CRANKCASE PORTIONWITHIN SAID WALLS RECEIVING AND SUPPORTING SAID CYLINDERS; AN UPPERPORTION WITHIN SAID WALLS RECEIVING AND SUPPORTING SAID CYLINDERS ANDHAVING PARALLEL CAM AND BALANCE SHAFT MOUNTING GALLERIES EXTENDINGLONGITUDINALLY THEREOF AND SYMMETRICALLY DISPOSED ON OPPOSITE SIDES OFSAID CYLINDERS, EITHER OF SAID GALLERIES BEING ADAPTED TO RECEIVE ACAMSHAFT OR A BALANCE SHAFT; AND A PLURALITY OF PAIRED TRANSVERSELYSPACED PARALLEL COLUMNS INWARDLY SPACED FROM SAID SIDE WALLS FOR